How to Fertilize Your Lawn

🧰 Tools & Materials

Tools

• Broadcast or drop spreader
• Work gloves
• Garden hose and sprinkler — if watering is required
• Measuring tape or measuring wheel — optional
• Broom or leaf blower

Materials

• Lawn fertilizer appropriate for your grass and soil
• Soil test kit — recommended if you haven’t tested recently

Before You Buy

Don’t choose lawn fertilizer simply because the bag promises a greener lawn.

The three numbers printed on fertilizer bags represent nitrogen, phosphorus, and potassium — commonly called N-P-K.

For example, a bag labeled 24-0-8 contains:

• 24% nitrogen
• 0% phosphate
• 8% potash

Nitrogen generally supports green leafy growth, phosphorus supports root development, and potassium contributes to overall plant health and stress tolerance.

What your lawn actually needs depends on your grass type, soil, season, and local conditions.

A soil test can help determine which nutrients are needed and prevent unnecessary fertilizer applications.

Also check the fertilizer bag for:

• Grass types it can be used on
• Square footage the bag covers
• Recommended application rate
• Spreader settings
• Watering instructions
• Temperature or seasonal restrictions
• How often the product can be applied
• Instructions for children and pets

💡 Pro Tip: More fertilizer does not mean greener grass. Applying too much — especially too much nitrogen — can burn the lawn and create excessive growth.

Before You Start

Figure out approximately how many square feet of lawn you’re treating.

For a basic rectangular area:

Length × Width = Square Feet

Measure separate lawn sections if necessary and add them together.

Subtract large areas that won’t receive fertilizer, such as the house, driveway, patio, garden beds, or pool.

You don’t need a surveyor-level measurement. You just need a reasonable estimate so you aren’t applying a bag intended for 10,000 square feet to a 4,000-square-foot lawn.

Also make sure the lawn is ready to be fertilized.

Avoid fertilizing:

• Severely drought-stressed grass
• Dormant grass unless the product and timing are appropriate
• Immediately before heavy rain
• During inappropriate temperatures for the product
• More frequently than the label allows

If the lawn is thin rather than simply lacking nutrients, fertilizer may not solve the entire problem. How to Overseed a Lawn covers how to thicken an existing lawn with new grass seed.

Step 1: Read the Fertilizer Label

Before opening the bag, read the application instructions from beginning to end.

Find the recommended application rate and locate the spreader-setting information.

Different fertilizers contain different concentrations of nutrients, so don’t reuse the application rate from the last fertilizer you bought.

Also check whether the lawn should be dry or damp during application and whether the fertilizer needs to be watered afterward.

What You Should See: Clear instructions telling you how much product to apply for a given lawn area and how the product should be watered.

If Yours Looks Different: If your exact spreader isn’t listed on the bag, check the spreader manufacturer’s recommendations or start with a conservative setting and apply the fertilizer evenly over the measured area.

Step 2: Set Up the Spreader

Place the spreader on a driveway, tarp, or other easy-to-clean surface before filling it.

Make sure the spreader opening is closed before pouring fertilizer into the hopper.

Set the spreader according to the fertilizer manufacturer’s recommendations.

Don’t fill the spreader while it’s sitting in the middle of the lawn. If fertilizer spills there, the concentrated pile can burn the grass.

What You Should See: Fertilizer sitting evenly inside the hopper with the spreader closed and ready to use.

If Yours Looks Different: If fertilizer immediately falls through the bottom, close the spreader gate before adding more product and clean up any concentrated piles.

💡 Pro Tip: Always start walking before opening the spreader and close it before you stop. This prevents fertilizer from dumping into one spot.

Step 3: Fertilize the Perimeter

Start by making a pass around the outside edge of the lawn.

Keep fertilizer away from flower beds, vegetable gardens, ponds, sidewalks, driveways, and other areas where you don’t want it.

A drop spreader provides more precise placement along edges, while a broadcast spreader throws fertilizer farther to each side.

If you’re using a broadcast spreader, pay attention to how far the granules are traveling.

What You Should See: A consistent perimeter pass without fertilizer being thrown heavily into landscaping or onto hard surfaces.

If Yours Looks Different: If granules are landing several feet into flower beds or across the driveway, reduce the spread pattern if your spreader allows it or move farther away from the edge.

Step 4: Apply Fertilizer Across the Lawn

Once the perimeter is complete, walk back and forth across the lawn in straight, consistent passes.

Maintain a steady walking speed.

With a broadcast spreader, allow the edge of each spread pattern to overlap slightly so you don’t leave untreated strips between passes.

Avoid excessive overlap, which can create darker green stripes or fertilizer burn.

What You Should See: Fertilizer distributed evenly across the lawn without visible piles, heavy stripes, or missed sections.

If Yours Looks Different: If you finish the lawn and have far more fertilizer left than expected — or run out halfway through — stop and double-check your lawn measurement and spreader setting before applying more.

Step 5: Clean Fertilizer Off Hard Surfaces

When you’re finished, inspect sidewalks, the driveway, patio edges, curbs, and other hard surfaces.

Sweep or blow stray fertilizer back onto the lawn.

Don’t hose fertilizer into the street or storm drain.

Besides wasting fertilizer, nutrients washed from hard surfaces can eventually reach streams, ponds, and other waterways.

What You Should See: Clean pavement with the fertilizer returned to the grass.

If Yours Looks Different: If a large amount landed on the pavement, check your spreader’s edge control or adjust your walking path before the next application.

Step 6: Water According to the Product Label

Some fertilizers need to be watered into the soil after application. Others have different instructions.

Follow the label rather than automatically turning on the sprinkler.

If watering is required, apply enough to move the fertilizer from the grass blades toward the soil without creating runoff.

Avoid applying fertilizer immediately before a major rainstorm. Heavy rain can move fertilizer away from where you intended it to go.

What You Should See: Fertilizer beginning to disappear from the grass blades and move toward the soil after appropriate watering.

If Yours Looks Different: If water is running across the lawn and into the street, stop watering and allow the soil time to absorb what you’ve already applied.

Step 7: Clean and Store the Spreader

Don’t leave fertilizer sitting inside the spreader after you’re finished.

Return unused fertilizer to its original bag or another appropriate labeled container according to the manufacturer’s storage instructions.

Clean the spreader as recommended by its manufacturer and allow it to dry before storage.

Store fertilizer somewhere dry and inaccessible to children and pets.

💡 Pro Tip: Fertilizer can attract moisture and become hard and clumpy. Keeping the bag tightly sealed and dry makes it much easier to use the next time.

Step 8: Watch the Lawn Over the Next Few Weeks

Give the fertilizer time to work.

Don’t apply another dose simply because the lawn doesn’t turn dark green within a few days.

Continue normal mowing and watering practices appropriate for your grass type.

If some areas remain thin or bare while the rest of the lawn improves, those areas may have a different problem.

For isolated damaged areas, use How to Fix Bare Spots in a Lawn rather than repeatedly applying more fertilizer.

What You Should See: Gradual improvement in grass color and growth rather than an overnight transformation.

If Yours Looks Different: Yellow, brown, or unusually dark stripes appearing after fertilization can indicate uneven application or excessive fertilizer.

🛑 Common Mistakes to Avoid

• Applying too much fertilizer: Excess fertilizer can burn grass and won’t make the lawn healthier.
• Guessing your lawn size: Knowing approximately how much area you’re treating makes proper application much easier.
• Using the wrong spreader setting: Settings vary by product and spreader.
• Stopping with the spreader open: This can dump concentrated fertilizer into one spot.
• Overlapping passes too much: Heavy overlap can create dark stripes or lawn damage.
• Fertilizing stressed grass: Severely drought-stressed or dormant lawns may not respond the way you expect.
• Fertilizing before heavy rain: Runoff can carry nutrients away from the lawn.
• Leaving fertilizer on pavement: Sweep granules back onto the grass instead of washing them away.
• Fertilizing every time the lawn looks bad: Thin grass, weeds, compaction, poor drainage, and disease aren’t necessarily fertilizer problems.

Troubleshooting

Problem: Brown or yellow patches appeared after fertilizing.

You may have applied too much fertilizer or spilled a concentrated amount in that area. Follow the product manufacturer’s guidance and water appropriately if recommended.

Problem: Dark green stripes appeared across the lawn.

Your spreader passes may have overlapped too heavily, causing some sections to receive more fertilizer than others.

Problem: Light green stripes remain between passes.

The spread pattern may not have overlapped enough, leaving sections with less fertilizer.

Problem: The lawn isn’t getting greener.

Give the fertilizer time to work. If enough time has passed, the lawn may have another issue such as incorrect soil pH, compacted soil, drought stress, poor drainage, disease, or insufficient sunlight.

Problem: Weeds became more noticeable after fertilizing.

Fertilizer doesn’t distinguish between grass and weeds. If weeds are established throughout the lawn, follow How to Get Rid of Weeds in Your Lawn to determine the appropriate control method.

❓ FAQs

How often should I fertilize my lawn?

It depends on your grass type, climate, soil, and fertilizer. Follow recommendations appropriate for your specific lawn rather than fertilizing on a fixed schedule just because a certain amount of time has passed.

What do the three numbers on fertilizer mean?

They represent the percentage by weight of nitrogen, phosphate, and potash — commonly referred to as the N-P-K analysis.

Should I fertilize before or after mowing?

Follow the fertilizer label. In many cases, mowing beforehand can make application easier, but avoid stressing the lawn by cutting it excessively short.

Should I water after fertilizing?

It depends on the product. Many granular fertilizers are watered in, while other products may have different requirements. Always follow the label.

Can fertilizer burn my lawn?

Yes. Excessive fertilizer, spills, improper application, or applying certain products under unfavorable conditions can damage grass.

Can I fertilize and overseed at the same time?

Sometimes. Starter fertilizer is commonly used during seeding, but the appropriate fertilizer depends on your soil and local regulations. See How to Overseed a Lawn for the complete overseeding process.

Can I fertilize a wet lawn?

That depends on the fertilizer. Some products are intended for application to dry grass, while others have different requirements. Check the label before applying.

Is weed and feed the same as regular fertilizer?

No. Weed-and-feed products combine fertilizer with herbicide. They should only be used when the lawn actually needs both treatments and when the product is appropriate for your grass and weeds.

📞 When to Call a Professional

Fertilizing a lawn is usually an easy DIY project.

Consider calling a lawn-care professional or contacting your local extension service if:

• You aren’t sure what type of grass you have
• A soil test reveals a significant nutrient or pH problem
• Large areas continue dying despite proper lawn care
• You suspect disease or insect damage
• Fertilizer applications repeatedly damage the lawn
• The lawn has major drainage or soil problems
• You’re unsure which products are appropriate for your property

Related DIY Guides

• How to Overseed a Lawn
• How to Fix Bare Spots in a Lawn
• How to Get Rid of Weeds in Your Lawn
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